The dualling of the A8 road to Larne, Co Antrim, will boost the attractiveness of the town's port for business and tourist traffic and increase Northern Ireland's competitiveness.

"This is very welcome news," Nigel Smyth, regional director of the CBI, said. "The A8 is a key part of the strategic road network in Northern Ireland and its upgrading has been a CBI priority for several years.

"This will this improve our connectivity with the Port of Larne, improving average speeds and journey time reliability on this important route, especially for freight and tourism traffic.

"In the short-term this investment will also provide a much needed boost to the construction sector and job creation."

He said competition between the ports was "helpful".

A consortium of Lagan, Ferrovial and Costain will work on the £100m upgrade, which will start next month after a nine mile route was approved by Regional Development Minister Danny Kennedy.

It will entail a bypass of the village of Ballynure despite objections by businesses in the village.

The Port of Larne, owned by P-amp;O which operates the fastest crossing from Ireland to Scotland on the Larne to Cairnryan route, said the department's strategy had recognised the port's importance as a gateway .

"The port has waited for many years for this final piece of dualling to be completed," a spokesman said. "This project, which will create a dual carriageway standard road connecting directly into the motorway network, is coming at just the right time to make sure the port can continue to compete effectively and to provide that vital key link across the Irish Sea."

Wesley Johnston, who maintains a website on road works in Northern Ireland, said the main benefit of the dualling would be to prevent long convoys getting stuck behind slow-moving vehicles such as tractors. Mr Johnston said: "I think it will make the road much safer and result in much more reliable journey times for users of Larne Port."